Automatic Differentiation was accepted as an experimental Rust feature for HPC, ML, and Scientific Computing applications. We present Rust-Enzyme, an LLVM-based autodiff tool and show that differentiating idiomatic Rust can lead to significantly better performance than differentiating similar C++ code. We will discuss rustc, LLVM, JAX, Enzyme and C++ limitations to explain benchmark differences and prove that old performance assumptions for libraries and languages won't hold when compiler-based automatic differentiation is applied.